The development of the inbred rabbits and other strains of rabbits which are genetically defined and serologically characterized continues to be the objective of this work. Inbreeding will continue through sib matings or its equivalent. The research studies include the development of the rabbit as a model for the investigation of problems in organ transplantation, blood transfusion and cancer immunotherapy. We will continue to expand our knowledge of the transplantation genes in the rabbit and study of the formal genetics of loci associated with the major histocompatibility complex. This includes linkage studies of the RL-A locus with genes controlling some immune responses, the MLC locus and a series of serum protein polymorphisms. We will also expand our studies on tumor induction and transplantation to develop the rabbit into a useful tool in cancer immunotherapy. The characterization of the rejection in the rabbit to organ and tumor transplants are being carried out.